Foot warmer



July 4, 1950 v. J. MORRIS 2,513,733

FOOT WARMER Filed June 28, 1947 2 Sheets-Sheet 1 FIG. 3. v 2/ I3 [20 /i7i2 [M- M n a n n n n n INVENTOR.

' VERGIL J1 MORE/.5

w v u u v u Mg wa ATTQRNEKS V. J. MORRIS July 4, 1950 FOOT WARMER 2Sheets-$heet 2 Filed June 28, 1947 FIG. 5.

FIG Z INVENTOR WERfi/L J MORRIS Patented July 4, 1950 UNITED STATESPATENT OFFICE FOOT WARMER Vergil J. Morris, Pasadena, Calif.

Application June 28, 1947, Serial No. 757,827

2 Claims. 1

This invention relates to a foot warmer. More particularly, theinvention relates to an apparatus in the form of a platform the uppersurface of which may be maintained at any desired temperature. The footwarmer of the invention is adapted to permit a person to warm his feeteither while standing thereon or while sitting on a chair or the like. v

The harmful effects of prolonged exposure of ones feet to cold ordampness are well known. Yet there are many occupations in which aperson must sit or stand for long periods in places which, in cold orwet weather, make difiicult the prevention of this undesirable exposureof the feet. For example, in open-air markets, service stations,drive-ins, and other semi-exposed places there has heretofore been noadequate means for protecting clerks, attendants, or the like from thisunhealthy condition.

Accordingly, it is an object of the present inaway.

vention to provide a foot warmer which will permit a person whilestanding or sitting to keep his feet at a uniformly warm temperature,without interfering with the carrying onof his regular duties, eventhough such duties involve exposure to adverse weather conditions.

Correlatively, it is an object of my invention to provide a foot warmerwhich may be conveniently moved about and may thus be positioned in themost desirable location to furnish protection to one whose dutiesalternately call him from place to place.

The above-contemplated objects are accomplished accordin to theinvention by means of an apparatus comprising a platform membercontaining a heating element disposed beneath the horizontal facethereof. As base member is affixed to the platform member. In oneembodiment of the invention, the base member is adapted to hermeticallyseal the heating element within the confines of the base member and theplatform. By sealing the heating elements within the closure, the footwarmer is unaffected by Water and will. operate even while standing in apuddle of water. The necessary electrical energy is supplied to theheating element which is preferably of the resistance wire type, bymeans of wires introduced through the vertical sides of the platformmember.

Other features and advantages of the foot warmer of the presentinvention will become apparent from the following description thereoftaken in relation to the accompanying drawing in which v Fig. 1 is anisometric view of the foot warmer;

Fig. 6 is a side elevation taken on the line 6-5 of Fig. 4 showing amodified form of the foot warmer of Figs. 4 and 5;

Fig. '7 is a sectional elevation taken on the line 1-4 of Fig. 6;

Fig. 8 is a partial plan View of another modification of the footwarmer;

Fig. 9 is a sectional elevation taken on 99 0f Fig, 8; and

Fig. 10 is a section taken on the line |lil0 of Fig. 6.

In Figs. 1 and 2, the foot warmer it! is shown to include the closuremember I l which is in the form of a platform the horizontal surface ofwhich is supported by the sides l2. In the embodiment here shown thehorizontal surface Ila of the platform or closure H and the sides l2 areshown making smooth continuous curves with each other. The horizontalsurface and the sides [2 may form right angles with each other withoutaffecting the operation of the foot warmer and the more streamlinedconstruction shown in Figs. 1 and 2 is rather for the purposes ofincreased mechanical strength than to aid in the operation of the footwarmer.

As seen in Fig. 2, the closure member or platform I1 is fitted over abase member 552 which is in the form of a box, the sides iii of whichare, in the preferred embodiment, lower than the sides l2 of the closuremember I I in order that the sides I2 will rest on the ground or floorwhen the closure is superimposed over the base is and will in thismanner provide a smooth bottom surface with the bottom of the basemember [3.

In the upper portion of the chamber formed by the base member [3 and theclosure member I I there is located one or more heating elements I 5.The heating elements It are spaced from the bottom of the base I3 bymeans of a quantity of insulation 16 shown in Fig. 2 as a plurality oflayers of insulation. In the preferred embodiment this insulationcomprises asbestos, Transite or the like and acts to prevent downwardheat loss from the heating element 15.

the line The heating element i5 is comprised in one embodiment of a coreI! of refractory non-conductive material such as, for example, mica,around which the resistance wire 20 is wrapped. Two layers [8 and I9 ofa similar refractory nonconductive material serve to insulate theresistance wires 20 from the metallic or conducting portions of the footwarmer.

In order to make the foot warmer of the invention particularly suitablewhere it is liable to come in contact with atmospheric moisture oractual pools of water, it has been so constructed in the embodimentshown in Figs. 1-3 that the heating element I5 is hermetically sealedfrom the atmosphere by the closure or platform member II. This is simplyaccomplished by so proportioning the member II and the base member i3that the vertical sides l2 of the member I I fit snugly around thevertical sides I4 of the member l3. To further insure the hermeticsealing, a coating 2! of a heat-resistant high temperature adhesive isemployed to join the sides of the closure member II to the sides of thebase [3. Any heatresistant adhesive may be employed for this purpose.Adhesives which are waterproof under a wide range of temperaturecondition and which are resistant to water, oil, gasoline and otherchemicals are to be preferred. Adhesives possessing these properties areavailable commercially. To further insure the waterproof joinder of theclosure member II to the base l3 a plurality of bolts or screws 22 maybe employed bolting together the sides of the two members and thusexerting a compression force on the adhesive layer 2|.

The required electrical energy is supplied to the heating elementsthrough a water-tight and air-tight conduit projecting through the walll2 of the platform member II and the wall l4 of the base l3 whichconduit carries a two or three Wire power supply into the windings ofthe heating element l5. To facilitate, assembly of the apparatus, thewall [4 of the base member, through which the power cable 2'6 projects,may be provided with a vertical slot 23 to receive the cable as theplatform member H, with the cable inserted therein is placed on thebase. The cable may thus be sealed in the platform member by the grommet21, prior to the assembling of the apparatus.

In the foot warmer as shown in Figs. 1 and 2, the exposed horizontalsurface Ha of the plat- ,form member H is criss-crossed longitudinallyand transversely with the grooves 24 and 25 respectively which providesfor drainage of water or the like so as to render the major portion ofthe surface more efiicient as a heating medium.

Looking downwardly on the foot warmer with the horizontal surface of theplatform H removed, one means of placement of the heating elements [5 isshown in Fig. 3. In the embodiment shown in Fig. 3 the foot warmer isprovided with a pair of similar heating elements con stitutingresistance wire 20 wound in a spiral ratus may be conveniently hooked incircuit with a rheostat or other variable resistance device in order tovary the temperature of the upper plate face of the platform ll overwide limits. However, the use of a rheostat may be obviated by theselection of a proper gauge size of Nichrome or other resistance wire inorder to produce a correct temperature at the prevailing voltage of theelectric energy source. Thus, if the foot warmer were to be employed inthe absence of a rheostat it would be desirable to employ a differentgauge wire if the electric energy were supplied from a 220 volt sourcethan if the energy were to be supplied from a volt source. However, bythe proper selection of the size resistance wire, the desiredtemperature could be obtained regardless of the voltage of the source.Alternatively a thermostat may be employed in the manner hereinafterdescribed.

In the embodiment shown in Fig. 3, the two heating elements I5 arespaced at opposite ends of the foot warmer and are separated by suitableseparators 24 and 25 and are continuously wound so as to be suppliedfrom one power source 26. As above described, the conducting wires fromthe external source are introduced to the foot warmer by means of thesealed conduit 21 and are connected to the heating elements at thecontact points 28 and 29. Although the two heating elements I 5 areshown to be connected in series, such is not a necessary feature of theinvention inasmuch as they may be operated with equally satisfactoryresults in parallel or independently. Further it is to be understoodthat although in the preferred embodiment of the invention'two heatingelements are employed, it is within the contemplation of the inventionto employ only one heating element containing the same or greaterfootage of resistance wire or to employ in excess of two heatingelements. In any case the temperature obtainable can be easilycontrolled by the control of the total footage of resistance wire and ofthe gauge size of the wire as well as by the proper selection of thetype of wire employed which, as stated above, may preferably consist ofNichrome resistance wire.

Whereas the invention has been described with relation to Figs. 1-3 as asealed unit, which may be employed in the presence of water, chemicalsor the like, in another embodiment of the invention the platform memberis fitted loosely over the base member. This embodiment possesses thedesirable feature of reduced manufacturing costs and ease of replacementof parts. A foot warmer of this type of construction is shown in Figs. 4and 5.

In the embodiment of the invention as shown in Figs. 4 and 5 the footwarmer 4|] comprises the platform member 4! and the bottom plate 42which together inclose the heating element (not shown), the insulation44 and the necessary wiring. The top of the platform 4| is cross hatchedas in the embodiment shown in Fig. 1 with the exception of a smoothsurfaced section in the center which is convenient for a name ortrademark or the like and a triangular elevated portion 46 on the edgethereof directly above the conduit 48 leading into the foot warmer. Thebottom plate 42 is affixed to the interior flange 50 of the platformmember 4| by means of the screws 5!, 52, 53, etc. Suitable waterproofsealing material is preferably used for sealing the bottom plate; andthe sealing material may be of the character heretofore described. Whenso affixed the plate 42 serves to hold the insulation in'thepositioncstablished by the guide-members 55; '56, l and 58projecteddownwardlyfrom theunder neath surface of the platform memberAll. Dis-= posed between the insulating sheet and the:

underneath surface ofthe platform member M is a heating elementsuchlashtheheating element shown in Figs. 2 and 3.

In thisiembodiment' or theinvention I may use either a single heatingelement or a plurality of heating elements; As shown in Fig. .10, whichis a section taken on the line Hll'l of Fig. 6, the conduit 48 isintroduced through the sidey4la' of the platform member andis sealedtherein by the packing and the packing gland 6i. Modi-- fications ofthis sealing arrangement may be made if -desired.- For example theelectrical conduit may be sealed through thewall by a suitable sealingmaterial of-the character described heretofore Preierablythe conduit 48carries three wires 63; 64-and65.- The-wires-fiit and 64" serve tosupply electricenergy to the heater and the wire 65. constitutes groundwire which is connected atthe endshown in Fig. 5 to the guide 55and atthe opposite end of the conduit 48' to ground.

In the embodiment of the invention shown in Fig. 5 a bimetallicthermostat 68 is disposed between the wire 63 and the heater and servesto make and break the contact therebetween responsive to the eifects oftemperature on the bimetallic elements.

A modified form of thermostatic control is shown in Figs. 6 and '7. Fig.6 is an elevation on the line 6-6 of Fig. 4 showing a section of theside 41a of the platform member and the triangular elevated portion 45which is formed integrally with the side. Fig. 7 is a sectionalelevation on the line 1-! of Fig. 6 showing an alternative means ofthermostatic control.

In Fig. '7 the thermostat 10 comprises the bimetallic element H providedwith the contact point 12 and the adjustable contact arm 13 providedwith the contact point 14.

The power supply is fed to the adjustable contact 13 by means of thewire 16 and the circuit is completed to the heater by means of the wire11 connected to the bimetallic element 1 I. The position of theadjustable contact arm 13 is controlled by the screw 8B passing throughthe side lla of the platform. To facilitate adjustment of the shaft 80 awing nut 82 is aflixed thereto.

As shown in Fig. 6 an indicating scale 84 may be provided on the sidemember l Ia adjacent the wing nut 82 so as to provide visual means forgauging the adjustment of the contact arm 13.

By mounting the thermostat 1D in a horizontal position the adjustmentmeans may be provided on the upper face of the triangular section 46.Such means of mounting the thermostat is is shown in the partial planview of Fig. 8 and the sectional elevation of Fig. 9 which is taken onthe line 89 of Fig. 8. In this embodiment the adjustment scale 80projects through the top of the elevated portion 46 and is provided atits outer end with an arm 86 whereby the adjustment of the contact arm13 is facilitated. As in the embodiment shown in Fig. 6 it is.convenient to provide an indicating scale such as the scale 81 adjacentone end of the arm 86 so as to furnish visual means of controlling theadjustment of the thermostat.

The most satisfactory material for construction of the foot warmer ismetal because of its high heat conductivity and mechanical strength.Although any materials may be employed for the base, it is substantiallyessential for eflicient operation that the platform member at least-thehorizontal portion thereof, .be of heat conductive materialto provideefficientheattransfer from the heating element through to the-heatingsurface of the platform. For this purpose, as well as for the basemember, the light metals such as aluminum, magnesium and alloys of theseand other light metals are superior although any metals may be employedand in fact, any structural: materials maybe employed. For purposes ofdurability and strength, steel, and particularly stainless. steel, maybe employed. To'provide greater-structurallstrength; oneor more.vertical- 8 support postsfmaybeemployed. One such sup--- portingmember3fl'i's shown in Figs. 2 and 3 projecting from the .baserl3- to theunder surface of I theplatform;;l The load carrying capacity of the,platform maybe. increased to-substantially any desiredamountbytheinclusion of one or more support; members; In the simplifiedembodiments shown in Figs; 4 and 5 such a supporting, post .is lessessential.

For the insulation-I61 spacing The heating elementss-ISyfrom'i'the:bottom of the base 13, in-

Figs. 1-3 and for the insulation 44 (Fig. 5) sheets of asbestos havebeen found to be highly satisfactory. If asbestos is employed in theform of sheets, a plurality of these sheets may be cut to the propersize and deposited in the base member l3 (Fig. '2) and thus be built upto the proper height to support the heating element [5 in proximity tothe under surface of the horizontal portion of the closure member H.However, any type of insulation material may be employed which willaccomplish the object of reducing the transfer of heat from the heatingelement 15 downwardly towards the bottom of the base member 13.

Other modifications in the apparatus of the invention will occur fromthe foregoing description and the following claims without departingfrom the spirit or scope of the invention which contemplates theprovision of a platformv type foot warmer which is preferably resistantto moisture, chemicals of any sort and other atmospheric conditions andwhich will accomplish the desired purpose under all types of adverseconditions.

I claim:

1. An apparatus of the class described, comprising a platform member oflight metal, said platform member consisting of a horizontal membersupported by continuous vertical sides, a base member of light metalencased by said platform member, said base member consisting of thebottom and four vertical sides held within and adjacent the respectivesides of the horizontal member, two heating elements disposed withinsaid base member and supported therein in a horizontal plane inproximity to the undersurface of said horizontal member of said platformand spaced from the bottom of said base member by a quantity ofinsulating material, said two heating elements being disposed withinsaid horizontal plane at opposite ends of said apparatus and beingconnected in series and to a power source, means for affixing saidplatform to said base member in hermetically sealed relationshipcomprising in combination a plurality of bolts joining the verticalsides of said members and exerting a compression force on aheat-resistant, chemical-resistant adhesive disposed between theadjoining faces of the vertical sides of said horizontal member and ofsaid base member, and a moisture-sealed conduit projecting through oneof the vertical sides of said base member and of said platformmembensaid conduit furnishing means for supplying power from an externalsource to said heating element.

2. Apparatus of the class described, comprising a metal platform member,said platform member consisting of a horizontal member supported bydepending sides which are substantially continuous, a base memberengaged by said platform member, said base member being held Within andadjacent to the respective sides of the horizontal member, heatinelement means disposed within said base member and supported therein ina horizontal plane in proximity to the under-surface of said horizontalmember of said platform and spaced from the base member by a quantity ofinsulating material, means for affixing said platform to said basemember in hermetically sealed relationship comprising a plurality ofbolts joining the periphery of the base member to the depending sidesand exerting a compression force on heat resistant, chemical resistantadhesive disposed between the adjoining surfaces of the base member andsaid sides, and a moisture-sealed conduit projecting through one of thedepending sides of said platform member, said conduit furnishing meansfor supplying power'from an external source to said heating element.

VERGIL J. MORRIS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,142,861 Van Wie et al June 15,1915 1,144,942 Lidberg June 29, 1915 1,257,106 Parkhurst Feb. 19, 19181,468,385 Lamb Sept. 18, 1928 1,644,255 Kercher et al Oct. 4, 19271,680,010 Brand Aug. '7, 1928 1,704,127 Hicks Mar. 5, 1929 1,892,298Bray Dec. 27, 1932 FOREIGN PATENTS Number Country Date France Oct. 16,1923

